An aircraft is propelled by several jet engines each housed in a nacelle also harboring a set of complementary devices related to its operation, such as a thrust reversal device or a defrosting system, for example.
The role of a thrust reversal device during landing of the aircraft is to improve its braking capability by redirecting forwards at least one portion of the thrust generated by the jet engine.
In this phase, the thrust reversal device obstructs the gas exhaust nozzle and directs the exhaust flow of the engine towards the front of the nacelle consequently generating a counter-thrust which will be added to the braking of the wheels of the airplane.
The means applied for achieving this re-orientation of flow vary depending on the type of inverter. However, in every case, the structure of the thrust reversal device comprises mobile cowls displaceable between an open position in which they open in the nacelle a passage intended for deflected flows and a closing position in which they close this passage. These mobile cowls may themselves fulfil the function of deflection or more simply a function of actuation of other deflection means such as flaps for obturating the jet.
Another important piece of electric equipment of a jet engine nacelle is the defrosting system for the air intake lip of the jet engine of the aircraft, which resorts to an electric system using a network of heating electrical resistors through which an electric current flows.
An important aspect of these nacelles using electrical systems is the management of the monitoring and control of these different devices of the nacelle.
For the thrust reversal device, the system for controlling displaceable elements presently consists of at least one assembly of electromechanical maneuvering members for maneuvering the elements which may be displaced between their closing and opening positions of the thrust inverter driven by at least one electronic control box of the ETRAS (acronym of Electrical Thrust Reverser Actuation Controller) type electrically connected to an engine control unit of the FADEC (acronym of Full Authority Digital Engine Control) type intended for controlling and monitoring the corresponding jet engine.
This electronic control box is a computer dedicated to the nacelle or to a portion of the latter (a displaceable element or a specific maneuvering member, for example), notably intended to express the orders for opening or closing the thrust inverter delivered by the FADEC into sequences for controlling the displaceable elements and the corresponding electromechanical maneuvering members and for informing the FADEC on the state of the maneuvering members and on the position of the displaceable elements on the other hand.
Although allowing self-management of the nacelle, this aircraft control system has drawbacks.
As the onboard computers are developing increasingly more functionalities related to the development of the devices of the aircraft and notably those related to the nacelle, the interconnections between these onboard computers, the cockpit of the aircraft and the FADEC are increasing.
The abundance of increasingly performing computers becomes detrimental for the communications network between these different computers, as well as for the electric power supply circuit required for their proper operation, making them more complex.
Many dimensioning constraints of the system in volume and mass are then imposed by this control system.
Indeed, the mechanical or communications interfaces as well as the required wirings and cable assemblies increase affecting the mass and the volume of the control system.
Further, the complexity of this control system increases the risks of failure, and the associated maintenance costs are then enhanced.